Lowerable a frame



2 Sheets-Sheet 2 Filed June 25-, 1962 ROBERT E. TALLEY INVENTOR ATTORNEY United States Patent 3,15%),2Q8 LQWERAhLE A FRAME Robert E. Talley, Racine, Wis, assignor to Bucyrns-lrre Company, South Milwaukee, Wis, a corporation of Delaware Filed June 25, 1952, Ser. No. 204,934 13 Claims. (til. 2l4-135) This invention relates to new and useful improvements in lowerable A frames for excavating or other machines equipped with booms, or the like.

In conventional power shovels, and similar machines employing an upwardly-inclined boom adjustable at different inclinations, the boom is raised and lowered by a hoist cable which passes from the point of the boom over a sheave on top of an A frame mounted relatively high above the main machine and thence to a hoisting drum on the main platform of the machine. It is desirable to have the A frame of such height that the angle of incidence of the hoist cable to the boom will be sufiicient to avoid high stresses in the hoist cable and in the boom. However, a high stationary A frame is objectionable since it must be removed to permit the machine to pass under bridges and like obstructions when it is transported on the highway. Therefore, the upper portion of the A frame is frequently designed so that it can be lowered to a position approximately horizontal with the top of the cab when the boom is lowered for transport.

In such machines the A frame is lowered by lowering the boom to the ground and then removing appropriate connections to the main frame thereby permitting the A frame to be lowered in a convenient manner, such as shown and described in U.S. Patent No. 2,609,939 to Trevor 0. Davidson and Bruno L. Lonngren.

Such boom suspension may cause strains to be transmitted to the boom at a place approximately midway between its points of support, thereby producing severe bending stresses. Accordingly, in many excavating operations it is desirable to use a boom of the type described in US. Patent No. 2,015,629 to Samuel Lippincott Griswold Knox, in which a short boom has boom struts at the outer end thereof.

However, to lower the A frame of a machine having a short boom, it is necessary to disconnect the rigid braces and to provide auxiliary means for lowering the boom to the ground. Such machines are somewhat limited to work which does not involve passing the machine through ways having a low overhead clearance.

It is therefore a principal object of this invention to provide a lowerable A frame for a machine:

(1) Which will automatically lower the boom to traveling position when the A frame is lowered.

(2) Which will jack-knife the boom strut when lowered sufiiciently to provide clearance between the dipper-handle assembly and the dipper and the ground.

(3) Which can during digging extend the cutting radius without altering the normal digging arc of the dipper.

(4) That can be lowered and raised without disassembling of parts.

(5) Which will combine the advantages of a guy-type suspension with the increased strength of a rigid strut suspension.

Other objects and advantages of the invention will be come apparent in the following description and drawings, of which:

FIGURE 1 is a side elevation of a power shovel embodying the invention;

FIGURE 2 is a plan view of the power shovel of FIG- URE 1;

FIGURE 3 is a side elevation of a power shovel having a second embodiment of the invention; and

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FIGURE 4 is a planview of the power shovel of FIG- URE 3.

Referring now to the disclosure of FIGURE 1, a power shovel is shown having traction mechanism 1 and main frame 2 to which an inclined boom 4 is connected by pivot pins 6. Connected to boom 4, preferably at the outer end thereof, by transverse pivot pins 5 are boom struts 3 supported at their outer end by fixed length guys '7 which are connected to shaft 9 of the mast 8 and by shaft 10 to the boom struts 3.

Mast 8 is pivotally mounted on A frame 11 by pivot pin 12 for fore-and-aft movement in the plane of the boom. Fixed-length rigid-boom support members 13 are pivotally connected to the mast, preferably to'the outer end thereof, by shaft 9, and to the boom, preferably at its outer end, by shipper shaft 14, thereby supporting the boom 4.

Variable length compression members 15 are pivotally connected at their upper ends to mast 8 by shaft 9 and at their lower ends to a point on main frame 2 adjacent the foot of the boom by pivot pins 16 thus supporting the outer end of the mast on the main frame. In their preferred form, compression members 15 consist of singleacting hydraulic-cylinder piston assemblies having cylinders 18 and pistons 17 (FIGURES 1 and 2), the latter being actuated outwardly by hydraulic fluid under pressure supplied through ports 19 from a conventional fluidpressure source (not shown).

Connected to shipper shaft 14 on the outer end of boom 4 is a conventional saddle block 20 in which is slidably mounted a dipper handle 21 carrying a dipper 22. Dipper handle 21 is pivoted about shipper shaft 14 by hoisting cables 23 which extend about sheaves 24 on the dipper and thence over sheaves 25 on the boom strut point to hoist drum 26 mounted on main frame 2.

FIGURE 1 shows the mast in its fully-raised or digging position, with pistons 17 fully extended in cylinder 18;

To lower mast 8 a fluid-pressure valve (not shown) is opened to allow fluid to flow through port 19 from cylinders 18 under pressure due to the weight of the boom, the dipper and dipper handle. As fluid is thus forced from cylinder 18, mast 8 is pivoted downwardly in a circular are about pivot pin 12 and rigid boom support members 13 carry boom 4 along a circular arc about pivot pin 6 (FIGURE 1).

Fixed length guys 7 cause the outer end of boom struts 3 to move along a curve resulting in a positioning of the end of the boom struts above the longitudinal plane of the boom when the boom is lowered.

When the fluid has been fully expelled from cylinders 18, masts 8 are completely lowered as shown in the dotted-line portion of FIGURE 1. The lower end of pistons 17 rest on stops 27 and the outer end of boom 4 is below a horizontal plane passed through pivot pin 6. The dipper and dipper arm are in a substantially horizontal position as a result of an increase in the distance between hoist drum 26 and boompoint sheave 25, and the mast, boom and dipper-handle assembly are in traveling position.

With a controlled retraction of cylinder-piston assemblies 15 through the action of the potential energy in the boom and dipper-handle assembly in forcing fluid through the fluid pressure valve, the following desirable results are obtained:

(1) Lowering of the mast to provide cab-height clearance.

(2) Lowering of the boom point to produce a clearance above the end of the boom, and counterclockwise rotation of the saddle block so that the dipper and dipper;

(3) Controlled increases in the cutting radius of the dipper for digging at a greater distance from the main frame of the machine without moving the machine.

FIGURES 3 and 4 show a second embodiment of the invention in which all of the elements are identical with those shown and described in the first embodiment except that hydraulic cylinder piston assemblies 15, A-frame 11 and masts =8 have been removed and there is substituted therefor masts 40' pivotally attached to the rear of main frame 2 by pivot pins 55 telescoping struts 41 pivotally connected to mast 40 by pivot pin 42 and to the main frame by pivot pin 43; and a variable length suspension means consisting of cable 44 anchored on sheave 45 at the outer end of the mast 4%, reeved on sheave 46 on pivot pin 47 at the rear of the main frame, reeved on a second sheave 48 on the mast and on a second sheave 49 at the rear of the main frame and thence wound on drum 50.

Struts 41 consist of lower elements 51 and upper elements 52, the former designed for telescoping within the latter, and the struts are held in extended position by pins 53 inserted through holes in adjacent ends of the telescoping elements.

Lowering of the mast in this embodiment is accomplished by removing pin 53 and paying out cable 44 un der the weight of the boom and dipper-handle assembly, thus telescoping the upper strut elements 52 within the lower strut elements 51 to a point limited by stops 54 in the feet of lower strut elements 51. Accordingly, when the lower ends of upper strut elements '52 rest on stops 51, the outer end of mast 4% is approximately in the plane of the top of main frame 2 as shown in dotted lines in FIG- URE 3.

To raise the mast from dotted-line to full-line positions (FIGURE 3), cable 44 is rewound on hoist drum 50 and pin 53 is again inserted in strut 41.

The invention described is applicable to other material handling machines such as cranes of the jib type in which the jib corresponds to the dipper handle and a mast strut for supporting said jib corresponds to the boom struts 3 of FIGURE 1. I

Having now described and illustrated two forms of this invention, it is to be understood that the invention is not to be limited to the specific form or arrangement of parts herein described and shown or specifically covered bythe claims. I

What is claimed is:

1. In a machine having a mainframe; a boom pivotally mounted thereon; a dipper handle assembly carrying a dipper at its outer end, said dipper handle being operatively related to the boom; a hoisting cable operatively attached to the dipper and extending to hoisting machinery on the main frame; the combination of: a gravity lowerable mast having its foot pivotally connected to the main frame; a first fixed-length means connecting the outer end of the mast to the boom; power means for pivoting said mast to raised positions and for supporting the mast in a raised position; a boom strut pivotally connected to the outer end of the'boom carrying a sheave over which passes said hoisting cable; and a second fixed-length means connecting the outer end of said bo'om strut to said mast. I 2. In a machine having a main frame; and a boom pivotally mounted thereon; the combination of: a gravity lowerable mast, pivotally mounted on said main frame, fixed-length means connecting the outer end of the boom to the mast; a dipper handle assembly carrying a dipper on its outer end, said dipper handle assembly operatively related to the boom; a boom strut extending from'said boom; a hoisting cable operatively attached to the dipper and extending to hoisting machinery on the main frame; a

sheave over which passes said hoisting cable, supported by the outer end of the boom strut; a guy of set length connecting said mast with said boom strut; an extensible and fellactible m mber for retaining said mast normally in elevated position, said retainingmeans being releasable for lowering the mast; and power means for pivoting the mast to its raised position.

3. In 'a machine of the character described according to claim 2, further characterized by the fact that the extensible and retractable retaining means comprises a telescoping compression member and an extensible and retractable tension member for extending said compression member, and means for fixing said compression member in extended position. I H

4. In a machine of the character described according to claim 2, further characterized by the fact that the means connecting the boom to the mast comprises rigid struts rendering the outer ends of the boom and the mast movable in unison fore and aft relative to the main frame.

5. In a machine of the character described; a main frame; a movable frame lowerable by gravity mounted thereon including an upwardly inclined boom pivotally supported adjacent the front of said main frame, a pivoted mast behind the boom, and a member between the mast and the boom; a dipper handle assembly carrying a dipper at its outer end, operatively related to the boom; a hoisting cable operatively attached to the dipper and extending to hoisting machinery on the main frame; power means for raising the movable frame and for supporting it raised; a boom strut disposed beyond and pivotally connected to the upper end of said boom and carrying a sheave over which passes said hoisting cable; and fixedv length tension means connecting the outer end ofsaid boom strut to the mast of said movable frame at a point rearwardly of the outer end of the boom strut for biasing said sheave upwardly as the boom is lowered. H

6. In a machine of the character described in claim 5 wherein the center line of the sheave is above a longitudinal transverse plane of the boom in lowered position.

7. In a machine of the character described in claim 5 wherein the center of the sheave is above a longitudinal transverse plane of the dipper handle when the boom is in lowered position.

8. In a machine of the character described in claim 5 wherein the dipper handle is supported by a shipper shaft mounted on said boom, and the center line of the sheave is above a horizontal plane through the shipper shaft when the boom is in lowered position.

9. In appaartus of the character described, in combination, a supporting structure, a boom pivotally supported in an inclined position upon said structure, a shipper shaft operatively related to the boom and mounted at the upper end thereof, a dipper handle under the control of said shipper shaft and carrying at itslower end a dipper, a hoisting rope operatively attached to said dipper and extending to hoisting machinery; a strut construction extending beyond said boom and carrying a sheave over which the hoisting rope passes, a gravity lowerable mast having its foot pivotally connected to said supporting structure, means of substantially fixed length connecting the outer end of the mast to the boom, power means for pivoting said mast to raised positions and for supporting the mast in a raised position, and means connecting said strut construction with said mast'for supporting the sheave above a horizontal plane through said pivotal support mounting of the boom on the supporting structure when the mast is in lowered position.

10. In a machine including a main frame; a movable frame lowerable by gravity mounted thereon including an upwardly inclined boom pivotally supported adjacent the front of said main frame; a member for material handling pivotally attached to said boom; power means for positioning said material handling member; means for raising the movable frame and for supporting it raised; a strut disposed beyond the upper end of said boom and operatively related to said power means; and tension means of substantially fixed length connecting the outer end of the strut to said movable frame at a point rearwardly of the outer end of the strut for biasing the outer end of said strut upwardly as the boom is lowered.

11. In an apparatus of the character described the combination comprising: a main supporting frame; a boom pivoted to said main frame with an outer end movable between raised and lowered positions; a framework on said main frame aft of said boom and including an upwardly extending mast lowerable to a retracted position; a support member extending between and connected to said boom and said mast; a boom strut pivoted to and extending outwardly from said boom as a continuation thereof; and a guy member extending between and connected to said mast and said boom strut; said support member controlling descent of said boom to said lowered position upon retraction of said mast, and said guy member controlling pivoting between said boom and boom strut upon retraction of said mast.

12. An apparatus in accordance with claim 11 in which said support member and said guy member are of set lengths, and said boom strut pivots upwardly with respect to said boom as said mast is retracted.

13. In an apparatus of the character described the combination comprising: a main supporting frame; a boom pivoted to said main frame with an outer end movable between raised and lowered positions; a boom strut pivoted to and extending outwardly from said boom as a continuation thereof; a support member connected to said boom retaining the same in raised position and movable for lowering the boom; and a guy member connected to said boom strut that is movable to lower the strut with the boom and to pivot the strut upwardly with respect to said boom as the latter is lowered.

References Cited in the file of this patent UNITED STATES PATENTS 2,073,539 Shelton Mar. 9, 1937 2,080,163 Busick May 11, 1937 2,572,336 Hall Oct. 23, 1951 2,774,484 White Dec. 18, 1956 2,809,756 Bannister Oct. 15, 1957 

1. IN A MACHINE HAVING A MAIN FRAME; A BOOM PIVOTALLY MOUNTED THEREON; A DIPPER HANDLE ASSEMBLY CARRYING A DIPPER AT ITS OUTER END, SAID DIPPER HANDLE BEING OPERATIVELY RELATED TO THE BOOM; A HOISTING CABLE OPERATIVELY ATTACHED TO THE DIPPER AND EXTENDING TO HOISTING MACHINERY ON THE MAIN FRAME; THE COMBINATION OF: A GRAVITY LOWERABLE MAST HAVING ITS FOOT PIVOTALLY CONNECTED TO THE MAIN FRAME; A FIRST FIXED-LENGTH MEANS CONNECTING THE OUTER END OF THE MAST TO THE BOOM; POWER MEANS FOR PIVOTING SAID MAST TO RAISED POSITIONS AND FOR 